Aiming at a kind of middle ear implant（MEI）, the driving voltage of a piezoelectric floating mass actuator is analyzed using a 0. 7Pb （Mg1/3Nb2/3） O3-0. 3PbTiO3 （ PMN- 30% PT）stack as a new type of vibrator. For...Aiming at a kind of middle ear implant（MEI）, the driving voltage of a piezoelectric floating mass actuator is analyzed using a 0. 7Pb （Mg1/3Nb2/3） O3-0. 3PbTiO3 （ PMN- 30% PT）stack as a new type of vibrator. For the purpose of facilitating the analysis, a simplified coupling model of the ossicular chain and the piezoelectric actuator is constructed. First, a finite element model of a human middle ear is constructed by reverse engineering technology, and the validity of this model is confirmed by comparing the simulated motion of the stapes footplate obtained by this model with experimental measurements. Then the displacement impedance of the incus long process is analyzed, and a single mass-spring-damper equivalent model of the ossicular chain attached with the clamp is derived. Finally, a simplified coupling model of the ossicular chain and the piezoelectric actuator is established and used to analyze the driving voltage property of the actuator. The results show that the required driving voltage decreases with the increase in the frequency, and the maximum required driving voltage is 20. 9 V in the voice frequencies. However, in the mid-high frequencies where most sensorineural hearing loss occurs, the maximum required driving voltage is 3.8 V, which meets the low-voltage and low-power requirements of the MEI.展开更多
This study investigates the photodegradation of the organic dye rhodamine B by Ag‐nanoparticlecontaining BiVO4catalysts under different irradiation conditions.The catalysts consist of Ag nanoparticles deposited on ox...This study investigates the photodegradation of the organic dye rhodamine B by Ag‐nanoparticlecontaining BiVO4catalysts under different irradiation conditions.The catalysts consist of Ag nanoparticles deposited on oxygen‐vacancy‐containing BiVO4.The morphology of the BiVO4is olive shaped,and it has a uniform size distribution.The BiVO4possesses a high oxygen vacancy density,and the resulting Ag nanoparticle‐BiVO4catalyst exhibits higher photocatalytic activity than BiVO4.The RhB degradation by the Ag nanoparticle‐BiVO4catalyst is99%after100min of simulated solar irradiation.BiVO4containing oxygen vacancies as a rationally designed support extends the catalyst response into the near‐infrared region,and facilitates the trapping and transfer of plasmonic hot electrons.The enhanced photocatalytic efficiency is attributed to charge transfer from the BiVO4to Ag nanoparticles,and surface plasmon resonance of the Ag nanoparticles.These insights into electron‐hole separation and charge transfer may arouse interest in solar‐driven wastewater treatment and water splitting.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satelli...The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satellites showed that energetic electron fluxes increased significantly during the storm recovery phase, and reached the maximum on October 6. The 1.5–14 MeV and 2.5–14 MeV electron fluxes observed by SAMPEX peaked around L=3.5 with values of 6×10 2 cm -2 s -1 sr -1 keV -1 and 5×10 3 cm -2 s -1 sr -1 keV -1 , which were about 10 and 8 times the pre-storm values. At the geostationary orbit, the >0.6 MeV and >2 MeV electron fluxes observed by GOES-10 showed enhancement up to 50 and 30 times. The plasma parameters and whistler-mode chorus waves in the outer radiation belt are also analyzed based on the data from Cluster C3 satellite. Cluster C3 satellite went through the outer radiation belt twice from 1 October to 4 October, and observed whistler-mode chorus waves with high intensity (10 -5 –10 -4 nT 2 Hz -1 ). Numerical calculations indicated that the observed chorus waves were in gyro-resonance with the radiation belt electrons. The current observations and calculations provide new evidence for that the gyro-resonance with chorus waves contribute significantly to the buildup of energetic outer zone electron fluxes during storms.展开更多
基金The National Natural Science Foundation of China(No10772121)the Med-Science Cross Research Foundation of Shanghai Jiao-tong University (NoYG2007MS14)
文摘Aiming at a kind of middle ear implant（MEI）, the driving voltage of a piezoelectric floating mass actuator is analyzed using a 0. 7Pb （Mg1/3Nb2/3） O3-0. 3PbTiO3 （ PMN- 30% PT）stack as a new type of vibrator. For the purpose of facilitating the analysis, a simplified coupling model of the ossicular chain and the piezoelectric actuator is constructed. First, a finite element model of a human middle ear is constructed by reverse engineering technology, and the validity of this model is confirmed by comparing the simulated motion of the stapes footplate obtained by this model with experimental measurements. Then the displacement impedance of the incus long process is analyzed, and a single mass-spring-damper equivalent model of the ossicular chain attached with the clamp is derived. Finally, a simplified coupling model of the ossicular chain and the piezoelectric actuator is established and used to analyze the driving voltage property of the actuator. The results show that the required driving voltage decreases with the increase in the frequency, and the maximum required driving voltage is 20. 9 V in the voice frequencies. However, in the mid-high frequencies where most sensorineural hearing loss occurs, the maximum required driving voltage is 3.8 V, which meets the low-voltage and low-power requirements of the MEI.
基金supported by the National Natural Science Foundation of China(21476033)~~
文摘This study investigates the photodegradation of the organic dye rhodamine B by Ag‐nanoparticlecontaining BiVO4catalysts under different irradiation conditions.The catalysts consist of Ag nanoparticles deposited on oxygen‐vacancy‐containing BiVO4.The morphology of the BiVO4is olive shaped,and it has a uniform size distribution.The BiVO4possesses a high oxygen vacancy density,and the resulting Ag nanoparticle‐BiVO4catalyst exhibits higher photocatalytic activity than BiVO4.The RhB degradation by the Ag nanoparticle‐BiVO4catalyst is99%after100min of simulated solar irradiation.BiVO4containing oxygen vacancies as a rationally designed support extends the catalyst response into the near‐infrared region,and facilitates the trapping and transfer of plasmonic hot electrons.The enhanced photocatalytic efficiency is attributed to charge transfer from the BiVO4to Ag nanoparticles,and surface plasmon resonance of the Ag nanoparticles.These insights into electron‐hole separation and charge transfer may arouse interest in solar‐driven wastewater treatment and water splitting.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40925014, 40874076)
文摘The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satellites showed that energetic electron fluxes increased significantly during the storm recovery phase, and reached the maximum on October 6. The 1.5–14 MeV and 2.5–14 MeV electron fluxes observed by SAMPEX peaked around L=3.5 with values of 6×10 2 cm -2 s -1 sr -1 keV -1 and 5×10 3 cm -2 s -1 sr -1 keV -1 , which were about 10 and 8 times the pre-storm values. At the geostationary orbit, the >0.6 MeV and >2 MeV electron fluxes observed by GOES-10 showed enhancement up to 50 and 30 times. The plasma parameters and whistler-mode chorus waves in the outer radiation belt are also analyzed based on the data from Cluster C3 satellite. Cluster C3 satellite went through the outer radiation belt twice from 1 October to 4 October, and observed whistler-mode chorus waves with high intensity (10 -5 –10 -4 nT 2 Hz -1 ). Numerical calculations indicated that the observed chorus waves were in gyro-resonance with the radiation belt electrons. The current observations and calculations provide new evidence for that the gyro-resonance with chorus waves contribute significantly to the buildup of energetic outer zone electron fluxes during storms.
